// Copyright (c) 2021, gottingen group.
// All rights reserved.
// Created by liyinbin lijippy@163.com

#include "abel/hardware/cpu_info.h"

namespace abel {

cpu_info::cpu_info()
        : signature_(0),
          type_(0),
          family_(0),
          model_(0),
          stepping_(0),
          ext_model_(0),
          ext_family_(0),
          has_mmx_(false),
          has_sse_(false),
          has_sse2_(false),
          has_sse3_(false),
          has_ssse3_(false),
          has_sse41_(false),
          has_sse42_(false),
          has_avx_(false),
          has_avx_hardware_(false),
          has_aesni_(false),
          has_non_stop_time_stamp_counter_(false),
          cpu_vendor_("unknown") {
    initialize();
}

namespace {

#if defined(ABEL_PROCESSOR_X86_64) || defined(ABEL_PROCESSOR_X86)
#ifndef _MSC_VER

#if defined(__pic__) && defined(__i386__)

void __cpuid(int cpu_info[4], int info_type) {
  __asm__ volatile (
    "mov %%ebx, %%edi\n"
    "cpuid\n"
    "xchg %%edi, %%ebx\n"
    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type)
  );
}

#else

void __cpuid(int cpu_info[4], int info_type) {
    __asm__ volatile (
    "cpuid \n\t"
    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type)
    );
}

#endif

// _xgetbv returns the value of an Intel Extended Control Register (XCR).
// Currently only XCR0 is defined by Intel so |xcr| should always be zero.
uint64_t _xgetbv(uint32_t xcr) {
    uint32_t eax, edx;

    // NOTE(gejun): xgetbv does not exist in gcc before 4.4, disable the use of
    // AVX instruction set.
#if defined(COMPILER_GCC) && \
    (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
    __asm__ volatile ("xgetbv" : "=a" (eax), "=d" (edx) : "c" (xcr));
#else
    __asm__ volatile (".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c"(xcr) : );
#endif
    return (static_cast<uint64_t>(edx) << 32) | eax;
}

#endif  // !_MSC_VER
#endif  //defined(ABEL_PROCESSOR_X86_64)|| defined(ABEL_PROCESSOR_X86)

#if defined(ABEL_PROCESSOR_ARM) && defined(ABEL_PLATFORM_LINUX)

// Returns the string found in /proc/cpuinfo under the key "model name" or
// "Processor". "model name" is used in Linux 3.8 and later (3.7 and later for
// arm64) and is shown once per cpu_info. "Processor" is used in earler versions and
// is shown only once at the top of /proc/cpuinfo regardless of the number CPUs.
std::string ParseCpuInfo() {
const char kModelNamePrefix[] = "model name\t: ";
const char kProcessorPrefix[] = "Processor\t: ";
std::string contents;
ReadFileToString(FilePath("/proc/cpuinfo"), &contents);
DCHECK(!contents.empty());
std::string cpu_brand;
if (!contents.empty()) {
std::istringstream iss(contents);
std::string line;
while (std::getline(iss, line)) {
if (line.compare(0, strlen(kModelNamePrefix), kModelNamePrefix) == 0) {
cpu_brand.assign(line.substr(strlen(kModelNamePrefix)));
break;
}
if (line.compare(0, strlen(kProcessorPrefix), kProcessorPrefix) == 0) {
cpu_brand.assign(line.substr(strlen(kProcessorPrefix)));
break;
}
}
}
return cpu_brand;
}

class LazyCpuInfoValue {
public:
LazyCpuInfoValue() : value_(ParseCpuInfo()) {}
const std::string& value() { return value_; }

private:
const std::string value_;
DISALLOW_COPY_AND_ASSIGN(LazyCpuInfoValue);
};

qutil::LazyInstance<LazyCpuInfoValue> g_lazy_cpu_brand =
LAZY_INSTANCE_INITIALIZER;

const std::string& CpuBrandInfo() {
return g_lazy_cpu_brand.Get().value();
}

#endif  // defined(ARCH_CPU_ARM_FAMILY) && (defined(OS_ANDROID) ||
// defined(OS_LINUX))

}  // anonymous namespace

void cpu_info::initialize() {
#if defined(ABEL_PROCESSOR_X86_64) || defined(ABEL_PROCESSOR_X86)
    int cpu_info[4] = {-1};
    char cpu_string[48];

    // __cpuid with an InfoType argument of 0 returns the number of
    // valid Ids in CPUInfo[0] and the cpu_info identification string in
    // the other three array elements. The cpu_info identification string is
    // not in linear order. The code below arranges the information
    // in a human readable form. The human readable order is CPUInfo[1] |
    // CPUInfo[3] | CPUInfo[2]. CPUInfo[2] and CPUInfo[3] are swapped
    // before using memcpy to copy these three array elements to cpu_string.
    __cpuid(cpu_info, 0);
    int num_ids = cpu_info[0];
    std::swap(cpu_info[2], cpu_info[3]);
    memcpy(cpu_string, &cpu_info[1], 3 * sizeof(cpu_info[1]));
    cpu_vendor_.assign(cpu_string, 3 * sizeof(cpu_info[1]));

    // Interpret cpu_info feature information.
    if (num_ids > 0) {
        __cpuid(cpu_info, 1);
        signature_ = cpu_info[0];
        stepping_ = cpu_info[0] & 0xf;
        model_ = ((cpu_info[0] >> 4) & 0xf) + ((cpu_info[0] >> 12) & 0xf0);
        family_ = (cpu_info[0] >> 8) & 0xf;
        type_ = (cpu_info[0] >> 12) & 0x3;
        ext_model_ = (cpu_info[0] >> 16) & 0xf;
        ext_family_ = (cpu_info[0] >> 20) & 0xff;
        has_mmx_ = (cpu_info[3] & 0x00800000) != 0;
        has_sse_ = (cpu_info[3] & 0x02000000) != 0;
        has_sse2_ = (cpu_info[3] & 0x04000000) != 0;
        has_sse3_ = (cpu_info[2] & 0x00000001) != 0;
        has_ssse3_ = (cpu_info[2] & 0x00000200) != 0;
        has_sse41_ = (cpu_info[2] & 0x00080000) != 0;
        has_sse42_ = (cpu_info[2] & 0x00100000) != 0;
        has_avx_hardware_ =
                (cpu_info[2] & 0x10000000) != 0;
        // AVX instructions will generate an illegal instruction exception unless
        //   a) they are supported by the cpu_info,
        //   b) XSAVE is supported by the cpu_info and
        //   c) XSAVE is enabled by the kernel.
        // See http://software.intel.com/en-us/blogs/2011/04/14/is-avx-enabled
        //
        // In addition, we have observed some crashes with the xgetbv instruction
        // even after following Intel's example code. (See crbug.com/375968.)
        // Because of that, we also test the XSAVE bit because its description in
        // the CPUID documentation suggests that it signals xgetbv support.
        has_avx_ =
                has_avx_hardware_ &&
                (cpu_info[2] & 0x04000000) != 0 /* XSAVE */ &&
                (cpu_info[2] & 0x08000000) != 0 /* OSXSAVE */ &&
                (_xgetbv(0) & 6) == 6 /* XSAVE enabled by kernel */;
        has_aesni_ = (cpu_info[2] & 0x02000000) != 0;
    }

    // Get the brand string of the cpu.
    __cpuid(cpu_info, 0x80000000);
    const int parameter_end = 0x80000004;
    int max_parameter = cpu_info[0];

    if (cpu_info[0] >= parameter_end) {
        char *cpu_string_ptr = cpu_string;

        for (int parameter = 0x80000002; parameter <= parameter_end &&
                                         cpu_string_ptr < &cpu_string[sizeof(cpu_string)]; parameter++) {
            __cpuid(cpu_info, parameter);
            memcpy(cpu_string_ptr, cpu_info, sizeof(cpu_info));
            cpu_string_ptr += sizeof(cpu_info);
        }
        cpu_brand_.assign(cpu_string, cpu_string_ptr - cpu_string);
    }

    const int parameter_containing_non_stop_time_stamp_counter = 0x80000007;
    if (max_parameter >= parameter_containing_non_stop_time_stamp_counter) {
        __cpuid(cpu_info, parameter_containing_non_stop_time_stamp_counter);
        has_non_stop_time_stamp_counter_ = (cpu_info[3] & (1 << 8)) != 0;
    }
#elif defined(ABEL_PROCESSOR_ARM) && defined(ABEL_PLATFORM_LINUX)
    cpu_brand_.assign(CpuBrandInfo());
#endif
}

cpu_info::cpu_arch cpu_info::get_cpu_arch() const {
    if (has_avx()) return AVX;
    if (has_sse42()) return SSE42;
    if (has_sse41()) return SSE41;
    if (has_ssse3()) return SSSE3;
    if (has_sse3()) return SSE3;
    if (has_sse2()) return SSE2;
    if (has_sse()) return SSE;
    return PENTIUM;
}
}  // namespace abel

